In magnetic recording technology, the current trend is to higher density media. Such higher density media are achieved by utilizing a smaller track width. As a result, heads which can write to and read from such small track width, higher density media are of increasing interest. In particular, it would be desirable to obtain a magnetic element capable of being used in a read head for recording densities of greater than one hundred and fifty gigabytes per square inch.
FIG. 1 depicts a conventional magnetic element 10 that is of interest because it might be capable of reading such higher density media. The conventional magnetic element 10 is a conventional spin valve that includes a conventional current confinement layer (CCL) 60. The conventional magnetic element 10 also includes a conventional antiferromagnetic (AFM) layer 20, a conventional pinned layer 30, a conventional nonmagnetic spacer layer 40, a conventional free layer 50, and a conventional capping layer 70. In addition, seed layers (not shown) and lead layers (not shown) are typically also used.
The conventional magnetic element 10 shown utilizes PtMn for the AFM layer 20 and Cu for the conventional nonmagnetic spacer layer 40. The conventional pinned layer 30 is also synthetic, including conventional ferromagnetic layers 32 and 36 separated by the conventional spacer layer 34. The conventional ferromagnetic layers 32 and 36 are typically composed of materials such as CoFe, while the conventional spacer layer 34 is typically composed of Ru and has a thickness such that the conventional ferromagnetic layers 32 and 36 are antiferromagnetically aligned.
In order to use the conventional magnetic element 10 at higher densities, current is typically driven in a current perpendicular to plane (CPP) configuration. In the CPP configuration, current is driven vertically as shown in FIG. 1. In order to increase the conventional CCL 60 is incorporated into the conventional magnetic element 10. The conventional CCL 60 includes conventional conductive nano-dots 62 in an insulating matrix 64. At least some of the conventional nano-dots 62 (and all that are shown in FIG. 1) extend completely through the insulating matrix 64. In operation, current driven through the conventional magnetic element 10 in the CPP configuration is restricted to the conventional nano-dots 62 in the conventional CCL 60. In the remainder of the conventional magnetic element 10, therefore, current is weakly confined to the regions vertically aligned with the conventional nano-dots 62. Because the current is effectively confined to narrow regions within the conventional magnetic element 10, the signal is improved.
Although the conventional magnetic element 10 may function in principle, one of ordinary skill in the art will recognize that there are drawbacks to the conventional CCL 60. In particular, the conventional CCL 60 is typically formed by depositing a layer including metal, and then oxidizing the layer. The formation of the conventional nano-dots 62 is difficult to control in such a process. Consequently, as depicted in FIG. 1, the size and/or distribution of the conventional nano-dots 62 may be nonuniform. Furthermore, the thermal stability of such a conventional CCL is poor. For example, the size and distribution of the nano-dots 62 may vary widely after an anneal. Thus, in practice, the conventional magnetic element 10 may be difficult to incorporate into a reliable working device.
Accordingly, what is needed is a system and method for providing an improved magnetic element capable of being used at higher densities. The present invention addresses such a need.